Improvement in balanced slide-valves



v 2 Sheets-Sheth 7 EM. HAM'BLIN.

Balanced Slid Valve. No. 202,025. "Patented April 2,1878.

ATTQRN Y NPETERS. PHOTD-LITHOGRAPNER. WASNINGYON. D Cv QR! m2 um.

H. M; HAMBLIN. Balalic-ed "Slide Valve. No 202,025. Patented April 2,18.78.

2 Sheets--Sheet'2,

UNIT D STATES PATENT OFFICE.

HENRY M. HAMBLIN, OF GREENVILLE, PENNSYLVANIA.

IMPROVEMENT IN BALANCED SLIDE-VALVES.

. Specification forming part of Letters Patent No. 262,625, dated April2,1878; March 11, 1878.

To all whom it may concern. 7

Be it known that I, HENRY M. HAMBLIN, of Greenville, in the county ofMercer and State of Pennsylvania, have invented certain new andiusefulImprovements in Balanced Slide- Valves; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it pertains tomake and use it, reference being had to the accompanying drawings, whichform part of this specification. b

My invention relates to an improved balance slide-valve forsteam-engines; the object being to provide a slide-valve of suchconstruction that live steam may be admitted,

and caused to exert an upward pressure on,

the entire lower surface of the back of the valve, and also introducedthrough the valve into the steam-chest, and exert a pressure on theupper surface of the valve, so that the downward pressure will beslightly in excess of the upward pressure on the valve and practicallybalance the same.

In the accompanying drawings, Figure 1 represents a vertical section ofmy improved balanced valve as applied to a steam-cylinder, the valvebeing shown in proper position for conducting steam to one end, andexhausting from the other end, of the cylinder. Fig. 2 represents asimilar view, showing the steamports cut off and the exhaust-ports open.Fig. 3 is a plan view of the valve-seat, and Fig. 4 a plan view of theface of the valve.

A represents a steam-cylinder, provided with an ordinary piston, B. O Gare exhaust-passages leading from the exhaust-ports D D in thevalve-seat E to the lower side of the cylinder, where they converge andunite in the single exhaust-outlet F. The valve-seat E is provided withthe main steam-induction port G and end ports H H, which connect withsteam-passages a a, leading to opposite ends of steam-cylinder A. I is asteam-valve of the class termed as the B slide-valve. It is providedwith two arched bridges, b b, which serve as exhaust-passages. Theopposite ends of the valves are formed with steampassages c 0, while thecentral portion of the valve between the bridges b b constitutes themain steam-inletpassaged. Withinthecentral application filed passage d,I secure or form in the process of "casting the valve two smallsteam-passages,

Q which form anopen passage through the back of the valve. J is thevalve-rod, and is attached to the valve by means of a nut or slide, K,which fits within guides on the end of the valve, wherebythe latter isallowed free vertical movement when in operation.

They operation of my improved balanced valve is as follows: Whenthevalve is in the position illustrated in Fig. 1, live steam flows fromthe main induction-port G into the interior portion of the valve throughthe central andmain steam-passage d, over the arched bridge b, throughthe end passage 0 in the valve, and into the steam-port H, and fromthenceto the end of the cylinder through the steam-passage a, andoperates to drive the piston to the right hand of the cylinder, as

indicated by the arrow. The confined steam on the opposite side of thepiston flows through the steam-passage a, through the steam-port H intothe recess in the arched bridge I), and from thence through theexhaust-port D to the outlet F through the exhaust-passage C.

It will be observed that the effect of the upward pressure of steam onthe under side of the valve is to raise the valve from its seat.

To counterbalance the upward pressure the small vertical ports e e areemployed, which have the following effect: When the valve is in theposition above described, the tendency is not only to raise the valvefrom its seat,but also to raise one end of the valve higher than theother, and hence my object is to admit steam to the valve in such amanner as will not only equalize the pressure on the valve, butdistribute the pressure in such a manner that all tendency to unequalpressure on the ends of the valve will be obviated.

When the steam is flowing through one end of the valve and exhaustingthrough the opposite end thereof, it is obvious that the com bined forceand momentum of the inflowing steam flowing upward against one end ofthe valve has a tendency .to raise that end of the valve to a greaterextent than has the confined steam in the opposite end of the valve,which latter is held to its seat by the fact that it is open to theexhaust, and hence, by allowing the steam to enter through thesteam-passage e, located nearest that end of the valve through whichsteam is being supplied to the cylinder, that end of the valve will beheld to its seat by the pressure of steam acting on the upper surface ofthe valve. When the valve is in the position represented in Fig. 2, thesteampassages e e overlap the main steam-inlet sufliciently to allowfree passage of steam to the back of the valve and balance of the same.

The initial cost of applying my improved valve to new or old engines isslight, and but a slight and comparatively inexpensive change in theconstruction of the valve is necessary to efiect the desired result.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a balancedvalve, the combination, with a hollow valve providedwith independent exhaust-steam passages, of independent steampassages ee, extending from the face of the valve upward through the back of thevalve, substantially as set forth. A

2. The combination, with a valve-seat pro vided with steam-ports G H Hand exhaustports D D, of a hollow valve formed with steam-ports d 0 0independent exhaust-passages b b, and steam-passages e e, substantiallyas set forth.

3. A hollow balanced valve provided with:

two independent exhaust-passages, and with steam-passages located in themain steaminduction passage of the valve, said steampassages arrangedand adapted to supply steam intermittingly to the back of the valve,substantially as set forth;

4. A balanced hollow valve having one main central inlet-port and twodischargeports leading therefrom, and having two independenteXhaust-passages located on either side of the main inlet-port, andbetween said inlet-port and the said discharge-passages,

and having independent live-steam passages in the back of the valve,said passages located in the live-steam passages, and constructed so asto admit live steam intermittingly to the back of the valve, said valveadapted to have free vertical movement in the valve-chest, substantiallyas described.

In testimony that I claim the foregoing 1 have hereunto set my hand.

HENRY M. HAMB LIN.

Witnesses J. K. HAMBLIN, J t G. HAMBLIN.

